Not sure how active it is outside large US cities but I've been using Beli (https://beliapp.com/) for the past couple years. It's essentially friends stack-ranking restaurants they've been to, which is useful because I can adjust for their biases -- they care varying amounts about service, cleanliness, authenticity, creativity, ambiance, etc. I regularly find new spots through friends and can decide if I trust their taste enough to order/check it out in person.

Only downside is it's pretty limited to the yuppie-foodie crowd - like in NYC, once you venture into deeper Brooklyn/Queens/The Bronx, you won't find much on there.